SHEET INSTABILITY SOLUTIONS WORLD PULP&PAPER 54 the dryer. There will be no surfaces actively collecting paper scrap as a result of a web break since there is no contact between the stabilisers and the dryer felts. The narrow distance between the high release nozzle and the dryer felt in combination with a high air flow velocity will ensure that no paper scrap build-up will occur on the high release nozzle surface. The mill pressurised air needed for the tail threading function of this concept is equal to that of traditional rope The development of the high release nozzle enables… low pressure levels to be reached without the need for a cross- machine air nozzle on the up-run side cylinders will be created through the vacuum connections in the stabiliser. Thus, only minor modifications are needed to the cylinder or rolls in connection with this kind of a process conversion. The ropeless tail threading will be further secured through installation of a variety of tail threading technology solutions – all being tailor-made for each application and need. IMPROVED ENERGY EFFICIENCY The increased energy input used by the compressor and needed with the high release nozzles compared to traditional nozzles is offset by the cost savings in the reduced number of web breaks, the reduced time required for cleaning work and tail threading following a web break. The negative pressure level needed on the dryer fabric side of the opening nip is highly dependent on the production speed. This negative pressure has to counter the negative pressure created on the paper side, thus making the paper follow the fabric surface and not the cylinder. The development of the high release nozzle enables these low pressure levels to be reached without the need for a cross-machine air nozzle on the up-run side. This can reduce the electrical energy needed for the traditional air systems installation by more than 40%, without any increase needed in the compressed air system. In addition, less investment is needed in traditional air system equipment and rebuild lay- out solutions and demands. It is quite normal for the main part of the existing stabiliser air systems, based on the dimensioning criteria to be re-used in these rebuilds. Air to the high release nozzles is produced with a low-pressure compressor and the optimal conditions (air flows and pressure levels) are efficiently adjusted through the loading of the compressor motor. Hoses are used for the air connections to the stabilisers. In wide machines (or those with a narrow geometry between the top and bottom cylinders), any large air duct connection will reduce the space for cleaning work and accessibility to Figure 2. Principle of EV EasyOne concept.